Project facts:
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Client
Recreatieschap Rottemeren
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Organisation Water Board HHSK, province of South Holland, Staatsbosbeheer
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Implementation period 2021
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Project budget > € 20.000
The challenge
The Rottemeren is a vast forest and lake area on the outskirts of Rotterdam, Lansingerland, Zuidplas and Zoetermeer. The lakes are connected by the ancient peat river De Rotte. At various locations, the steep and narrow shores are slowly caving in, due to currents and wind. The risk is that the protection of the embankments will be undermined. There are also risks for the existing underground and above-ground infrastructure. In order to prevent further erosion, shore protection must be constructed, repaired or improved. The manager of the river, Recreatieschap Rottemeren, is striving for a nature-friendly solution.
Our activities
Recreatieschap Rottemeren (part of the governmental organization Staatsbosbeheer) commissioned Walhout Civil to inspect and advice for a nature-friendly restoration of the shores along De Rotte (approx. 7 km) and the Hoge Bergse Bos (approx. 2 km). Based on the inspections, the manager has obtained an overall picture of the current situation, the damage and a appropriate solution. And summary of our activities:
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Geotechnical research, drilling and CPTs
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Inspection and damage assessments
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Engineering nature-friendly shores
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Cost estimations per solution
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Coordination with Client and stakeholders
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Drawings with situation and cross sections
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Reporting with photo reporting
Deployment research vessel Dyckgraaf
Inspecting the situation is quite a challenge due to the steep and narrow shores. The presence of infrastructure, buildings, waterworks, jetties and vessels creates a lot of obstacles. However, due to the deployment of the SAR research vessel Dyckgraaf, it was still possible to inspect well even at a limited draft. All embankments have been photographed and measured. The cross sections obtained formed the basis for the design and determination of the quantities.
Engineering wooden sheet pile
Geotechnical research was carried out for the design of the solution near the historic lock 'Zevenhuizer Verlaat'. An anchored quay construction with an Azobé wooden sheet pile has been set up on the basis of a few CPTs and drillings. The construction is completed with erosion-resistant clay. Wood is recycled where possible.